20+ usable planets per solar system is pretty crazy... I know ppl have brought this up before, and I feel like its a very important "fact" that needs addressing.
A 4x galactic conquest game could consist of 100's of star systems (or at lest 10-20 in smaller games).
Look at our own solar system... When related to Sins...
Mercury, Earth, Mars, Uranus, and maybe Pluto (not counting any moons) are the only usable planets (as whats currently usable in Sins). So why would every system in Sins consist of so many planets when most common systems we've discovered are similar to our own?